The invention relates to a brush holder for an electrical commutating machine, in particular for a d.c. machine for vehicles. More particularly the present invention relates to such a brush holder which has a brush plate supported in the frame of the commutating machine, and at least two brush mounts fastened in an insulating fashion on the brush plate and each accommodating a carbon brush and provided on their bearing side with a pull-through pin and a supporting web.
Apart from the insulating plate arranged between the brush mount with supporting web and brush plate, in a known brush holder of the above-mentioned type in order to ensure the insulated fastening of the brush mount on the brush plate, a first insulating disc is arranged between the brush plate and the rivet head overreaching the brush plate, and a second insulating plate is inserted between the rivet shaft and the bore, substantially larger in comparison thereto, in the brush plate. The entire brush mount is supported by the single rivet bolt.
In the case of extreme stresses on the commutating machine owing to impacts, shaking or severe temperature fluctuations, such as normally occur in vehicle operation, it has been found in connection with such brush holders that the brush mounts rotate on the brush plate and assume angular positions with respect to the commutator which are detrimental to proper commutating.
Consequently, in the case of a brush holder that is likewise known (U.S. Pat. No. 1,490,104) two supporting webs have been provided on the brush mount, and each supporting web has been riveted to the brush plate with the interposition of suitable insulating discs. Due to the double riveting, the assembly of such a brush holder is more intensive in terms of time. Again, the brush mount needs to be altered in design.